Raymond Samuel Tomlinson, who is credited with inventing email and putting the now ubiquitous “@” sign in addresses, has died at the age of 74.

Tomlinson, who helped in the evolution of single-computer email into electronic mail that could send communications across network connections to other hosts, used the sign in the address to connect the user name with the destination address and provide a way to distinguish local mail from network mail.

“I chose to append an at sign and the host name to the user's (login) name. I am frequently asked why I chose the at sign, but the at sign just makes sense,” he wrote in a post about the first network email. “The purpose of the at sign (in English) was to indicate a unit price (for example, 10 items @ $1.95). I used the at sign to indicate that the user was "at" some other host rather than being local.”

By doing this, he could have saved the sign from extinction as some were considering removing it from the keyboard, he wrote.

In an interview to Computerworld in 2007, Tomlinson said that of all the available punctuation marks available on the keyboard only the “At” sign conveyed a sense of place. He could have used the "On" or "Of" signs for the purpose, but there are no such characters, he added.

Born in Amsterdam, New York in 1941, Tomlinson studied at MIT after attending college at the Rensselaer Polytechnic Institute, where he received a Bachelor of Science degree in electrical engineering in 1963, according to his Internet Hall of Fame biography. In 1967, he joined research and development company Bolt Beranek and Newman, which is now Raytheon BBN Technologies.

By 1971, Tomlinson developed ARPANET's first application for network email by combining the local inter-user mail program SNDMSG he was working on and an experimental file transfer program called CPYNET, allowing messages to be sent to users on other computers.

Tomlinson told Computerworld he wanted to build the first e-mail system that would allow messages to be sent from a person on one computer over a network to someone who was using an entirely different computer.

The death of Tomlinson has been mourned by a number of Internet notables including Vinton G. Cerf, Google’s chief Internet evangelist, who described the death of Tomlinson as “very sad news.” Google’s Gmail also tipped its hat to Tomlinson, thanking him for “inventing email and putting the @ sign on the map.”